ADC12 vs A380 -The Practical Difference

ADC12 and A380 are commonly called "equivalent." The differences are real and matter in specific contexts. This comparison explains when each is the correct specification.

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Side-by-Side

Parameter	ADC12 (JIS H5302)	A380 (ASTM B85)
Standard	Japanese JIS	American ASTM
Silicon	9.6-12.0%	7.5-8.5%
Copper	1.5-2.5%	3.0-4.0%
Tensile strength	310 MPa	317 MPa
Yield strength	160 MPa	159 MPa
Elongation	2.5%	3.5%
Hardness	85 HRB	80 HRB
Thermal conductivity	96 W/m·K	96 W/m·K
Castability	Slightly better (higher Si)	Excellent
Machinability	Excellent	Excellent
Corrosion resistance	Similar	Similar
Cost	±2% (similar)	Baseline

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The Silicon Difference

ADC12's higher silicon range (9.6-12.0% vs A380's 7.5-8.5%) provides:

• Better fluidity: Higher silicon keeps the alloy fluid longer during injection -marginal benefit in complex thin-wall automotive castings
• Slightly finer microstructure: More silicon particles per unit volume, marginally lower porosity tendency at equivalent process parameters
• Slightly harder: 85 vs 80 HRB -meaningful for wear surfaces; irrelevant for most structural applications

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The Copper Difference

A380's higher copper (3.0-4.0% vs ADC12's 1.5-2.5%) theoretically provides higher tensile strength -but the actual tensile difference is only 7 MPa (317 vs 310 MPa). Within production variation. Not a meaningful design factor for most applications.

The copper difference affects:

• Corrosion resistance (bare metal): A380's higher copper slightly reduces bare-metal corrosion resistance. For coated parts, irrelevant.
• Machinability: Both alloys are excellent -marginal improvement with A380.

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Decision Guide

Specify ADC12 when:

• Customer drawing or specification calls ADC12 or JIS H5302 by name
• Program is in a Japanese, Korean, or Asian OEM supply chain requiring JIS certification
• Japanese-format material certificates (Japanese-language material certificate are required

A380 is equally suitable when:

• North American or European customer specifications
• General industrial, commercial, and consumer applications
• ASTM B85 certification is the standard format required

For most programs, ADC12 and A380 are interchangeable. The decision is driven by supply chain standard and documentation format, not technical performance.

KastMfg stocks both alloys and certifies to either standard.

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Material selection consultation: yaoqingpu1983@gmail.com | +86 138 1403 4409